The presently disclosed subject matter relates to a probe which is to be attached to the finger of a subject to acquire physiological parameter of the subject.
JP-A-2007-029702 discloses a probe which is to be attached to the fingertip of a subject. The probe includes a light-emitting element and a light-detecting element. The light-detecting element has a light-detecting surface which detects a light beam that is emitted from the light-emitting element, and that is transmitted through the living tissue of the fingertip. The light-detecting element outputs a signal corresponding to the intensity of the light beam which is detected by the light-detecting surface. The light beam emitted from the light-emitting element is determined to have a wavelength at which a light beam is to be absorbed by a material in blood. The volume of blood in the fingertip is changed in accordance with the pulsation, and therefore also the intensity of the light beam which is detected by the light-detecting surface is changed. The signal output from the light-detecting element is used for calculating physiological parameter of the subject, such as the pulsation and the arterial oxygen saturation.
In the case where the fingertip of the subject is applied with nail polish or nail art, the light beam emitted from the light-emitting element may be absorbed by coloring matter of the nail polish or the nail art. In this case, there is a possibility that the light-detecting element may fail to detect a desired amount of light, and this may pose obstacles to calculation of physiological parameter.
The trouble of removing such a nail polish or nail art may cause a delay in taking a countermeasure in an emergency situation. On the other hand, such a nail polish or nail art includes expensive ones, and hence there is a need for, in a non-emergency situation, performing calculation of physiological parameter without removing a nail polish or nail art.
It is an object of the presently disclosed subject matter to enable physiological parameter to be accurately calculated regardless of presence or absence of a nail polish or nail art.